function minimumEntries(x, n, fc, fm)
// x:  an array
// n:  number of values
// fc: compare function (a, b)
// fm: map function (v, i, x)

const xarray = require('extra-array');

var x = [4, 2, 1, 3, 5];
xarray.minimumEntries(x, 2);
// → [ [ 2, 1 ], [ 1, 2 ] ]

xarray.minimumEntries(x, 3);
// → [ [ 2, 1 ], [ 1, 2 ], [ 3, 3 ] ]